Three-circuit snap-acting toggle switch



Dec. 2, 1969 c. E. SANFORD THREE-CIRCUIT SNAP-ACTING TOGGLE SWITCH 4 SheetsSheet 1 Filed May 12, 1967 INVENTOR CARLTON E. SANFORD }VWJ Dec. 2, 1969 I c. E. SANFORD 3,482,067

THREE-CIRCUIT SNAP-ACTING TOGGLE SWITCH Filed May 12, 1967 4 Sheets-Sheet 2 J r-" 'nl- 18 84 I115961 I a 86 INVENTOR CARLTUN E. SANFORD ATTORNEY m; MM

United States Patent 3,482,067 THREE-CIRCUIT SNAP-ACTING TOGGLE SWITCH Carlton E. Sanford, Riverside, R.I., assignor to Texas Instruments Incorporated, Dallas, Tex., a corporation of Delaware Filed May 12, 1967, Ser. No. 638,045 Int. Cl. H0111 21/04 US. Cl. 200-67 9 Claims ABSTRACT OF THE DISCLOSURE A three-position toggle switch, which alternately closes one of three circuits between a common contact and respective additional contacts, is shown to have a common contact in the form of a U-shaped bracket. This bracket has its central portion fixed to a base and has its ends upstanding from the base. Three additional contacts are spaced on the base and a contact arm means is rested across the upstanding ends of the U-shaped bracket to be rocked on the bracket into alternate engagement with the respective additional contacts. A toggle mounted on the base resiliently engages the central portion of the contact arm means between the upstanding ends of the U-shaped bracket to hold the contact arm means in engagement with the bracket contact and with one of the additional contacts for closing one circuit, the toggle being movable to either of two other alternate positions resiliently engaging respective end portions of the contact arm means for rocking the contact arm means on the bracket contact with snap action into alternate engagement with respective additional contacts for closing respective alternate circuits.

In aircraft and aerospace applications and the like, where a large number of controls must be mounted in a limited space, the switches employed should be as compact as possible while fulfilling the greatest possible number of functions. It is also desirable that such switches hold switch contacts firmly together in good electrical contact under conditions of severe vibration; that such switches open and close switch contacts rapidly to minimize contact arcing and wear; and, for many applications, that such switches have toggle actuating means which are easy to operate and which clearly indicate switch condition by observation of the position of the toggle means.

It is an object of this invention to provide a novel and improved toggle switch; to provide a toggle switch for alternately closing circuits between a contact and each of three additional contacts; to provide such a switch in which contacts are held firmly together in closed circuit position; to provide such a switch in which switch contacts are moved to open and closed circuit positions with snap-action for minimizing contact arcing and wear; to provide such a switch in which switch contacts are brought together with a wiping action to assure good electrical connection between the contacts; and to provide such a switch which is of simple, compact, rugged and inexpensive construction.

Briefly described, the toggle switch of this invention comprises a base having a common electrical contact which is in the form of an electrically conductive U- shaped bracket. This bracket contact is mounted with its central or bottom portion fixed to the base and with its end portions or arms upstanding from the base. Three additional contacts are fixedly mounted on the base in spaced relation to each other and to the U-shaped bracket. Terminal means are preferably connected to the respective contacts.

In accordance with this invention, electrically conductive contact arm means are rested across the upstanding 3,482,067 Patented Dec. 2, 1969 ice ends of the U-shaped bracket so that the ends of the contact arm means extend outwardly over each of the ends of the U-shaped bracket. The contact arm means preferably has three contacts resiliently mounted thereon, these contacts being adapted to engage the respective additional contacts mounted on the base for completing respective circuits between the U-shaped bracket contact and the additional contacts.

A toggle means is movably mounted on the base for resiliently bearing against the contact arm means to hold the contact arm means in firm engagement with the U- shaped bracket. The toggle means is movable along the contact arm means for rocking the contact arm means on the U-shaped bracket and for moving the contacts on the contact arm means with snap action into alternate engagement with the respective additional contacts on the base for completing respective circuits between the bracket contact and the additional contacts. That is, the toggle means normally engages the contact arm means at a location between the upstanding end portions of the U-shaped bracket, firmly holding the contact arm means in one switch position closing a circuit between the bracket contact and one of the fixed contacts on the base. When the toggle means is moved to resiliently bear against either extending end portion of the contact arm means, the contact arm means is rapidly rocked to a new switch position closing a circuit between the bracket contact and another of the fixed base contacts.

In this simple, compact, rugged and inexpensive construction, resilient engagement of the toggle means with the contact arm means opens and closes the switch contacts with snap action. This same resilient engagement holds switch contacts firmly together in closed circuit position. The resilient mounting of contacts on the contact arm means assures that a wiping action occurs when the contacts are brought into engagement with the fixed base contacts.

Other objects, advantages and details of the switch of this invention appear in the following detailed description of preferred embodiments of the invention, the description referring to the drawings in which:

FIG. 1 is a side elevation view of the toggle switch of this invention, with the switch housing partially cut away, showing the switch closing a circuit;

FIG. 2 is a section view along line 22 of FIG. 1;

FIG. 3 is a section view along line 33 of FIG. 1;

FIG. 4 is a section view along line 4-4 of FIG. 1;

FIG. 5 is a view similar to FIG. 1 showing the switch of FIG. 1 in an alternate switch position closing another circuit; and

FIG. 6 is a partial section view, to enlarged scale along line 66 of FIG. 2.

Referring to the drawings, 10 in FIGS. 1-3 and 5 indicates the novel and improved toggle switch of this invention which is shown to include two separate poles mounted in a common base or housing 12, the poles preferably being enclosed in separate housing compartments 14 and 16 to be actuated by a common toggle means 18. The toggle switch could be embodied in a single pole de vice or in other multipole devices within the scope of this invention. In describing the toggle switch of this invention, corresponding elements of each pole of the illustrated switch are identified by the same numerals.

As illustrated, the switch 10 includes a base or housing 12 which preferably includes a liner 20 of a ceramic ma terial, a phenolic resin or other suitably strong, electrically insulating material and a protective outer casing 22 of steel or other metal. A cover 24 is welded or otherwise secured to the casing in conventional manner.

In accordance with this invention, a U-shaped bracket contact 26 preferably formed of silver plated, cold rolled steel or other suitably rigid material of high electrical conductivity, has its central or bottom portion 28 secured to the base 30 of the insulating liner and has its ends or distal portions 32 and 34 upstanding from the base as shown. Terminal means 36 accessible from outside the housing are electrically connected to the bracket contact 26. For example, a bushing 38 of insulating material such as a phenolic resin is disposed in alignment with an aperture in the liner base 30 and an electrically conductive stud 40 is fitted within the bushing, the stud having a flange 42 engaging one end of the bushing 38 and having a staked or riveted end 44 holding the bracket contact 26 to the liner base. A terminal screw 46, together with a washer 48, is threadedly engaged with the stud 40 for facilitating attachment of a lead to the stud terminal. See FIGS. 3 and 4.

Three additional electrical contacts 50, 52 and 54 are fixedly mounted on the liner base 30 in spaced relation to each other and to the U-shaped bracket contact 26. For example, as illustrated particularly in FIG. 4, insulating bushings 56 are secured in apertures in the liner base and electrically conductive studs 58 are secured within the respective bushings in any conventional manner with stud flanges engaging one end of the bushings. Terminal screws 46 and washers 48 are then attached to the studs. The contacts 50, 52 and 54 are welded, soldered or otherwise secured to respective studs 58, the contacts preferably comprising a silver oxide alloy or other material of high conductivity. Although, the liner 20, the bushings 38 and 56, and the studs 40 and 58 may be mounted in the switch 10 as shown, it will be understood that the casing 22 could completely enclose the liner 20, and the terminal studs 40 and 58 could extend through the casing in insulated but hermetically sealed relation to the casing for hermetically sealing the switch 10.

In accordance with this invention, a contact arm means is rested upon the upstanding ends 32 and 34 of the U-shaped bracket contact 26 so that end portions of the contact arm means extend outwardly over the ends of the U-shaped bracket. In a preferred construction, the contact arm means includes a rigid, main contact arm member 72, preferably of cold rolled steel or other rigid material, the member preferably having two flat, central portions 74 forming an acute included angle which extends at least slightly downward to form a slight depression between the upstanding bracket arm 32 and 34. The end portions 76 and 78 of the member 72 extend out over respective ends of the bracket and are preferably turned slightly downward as illustrated in FIGS. 1 and 5. A correspondingly shaped resilient flexible member or strip 80 of electrically conductive material such as beryllium copper is attached to the rigid member 72, the resilient member supporting a pair of contacts 84 and 86 at respective ends of the resilient member. These contacts are preferably formed of the same material as the contacts 50, 52 and 54 and are preferably riveted or otherwise fixedly secured to the resilient member. A smaller rigid member 88 is also preferably attached to the opposite side of the resilient member 80', this rigid member having downwardly depending ears 90.

For example, the resilient member 80 is provided with apertures 81, as shown in FIG. 6, and pairs of weld projections 73 and 89 on the respective rigid members 72 and 88 fit within the apertures 81 and are welded together for trapping the resilient member between the rigid members. In this arrangement, the contact arm means 70 rests securely on the upstanding bracket arms 32 and 34 but is adapted to be rocked on the bracket as can be seen. For facilitating this rocking, the bracket 26 preferably has outwardly bent portions 92 engaging the contact arm means and preferably has ears 94 preventing lateral movement of the contact arm means on the bracket. Tabs 96 on the rigid member 72 engage the bracket cars 94 for preventing longitudinal movement of the contact arm means on the bracket.

In accordance with this invention a headed pivot pin 98 is welded or otherwise fixed to the bracket contact 26 to extend laterally from the bracket and a rigid, auxiliary contact arm 100 having downwardly depending ears 102 is rotatably mounted on the pivot pin 98. A resilient member or strip 104 is further welded or attached to the auxiliary arm 100 and carries a contact 106 at the distal end of the resilient member. The contact arm 100 is preferably of substantial length so that small angular movement of the arm provides substantial movement of the distal end of the arm. As shown particularly in FIG. 3, the auxiliary contact arm 100 and the resilient member 104 are apertured at 108 and an end 110 of a J-shaped pin 112 carried in the depending ears 90 of the rigid member 88 extends upwardly through this aperture to engage the top side of the resilient member 104. Preferably a washer 114 is carried on the end 110 of the pin and a helical coil compression spring 116 is mounted on the end 110 of the J-shaped pin between the washer 114 and the resilient member 104. Preferably a pigtail lead or braid or the like 118 is welded or otherwise secured in good electrical contact to the resilient member 106 and to the bracket contact 26 close to the pivot pin 98 for assuring electrical connection of the bracket and resilient member during pivoting of the auxiliary contact arm on the pin 98. Where the pigtail is close to the pin 98, pivoting of the auxiliary contact arm causes little or no wearing of the pigtail.

In accordance with this invention, the toggle actuating means 18 is pivotably mounted on the base or housing 12 for resiliently engaging the contact arm means 70. For example, in a preferred construction, an exteriorly threaded, preferably metallic, bushing 122 useful in mounting the toggle switch 10 on a control panel or the like is welded to the housing cover 24 as at 124 and a metal bellows 126 is fitted within the bushing as shown. A toggle supporting member 128 preferably having a flange 130 welded to the bushing 122 as at 132 has a central bore 134 and a slot 136 for receiving a toggle lever 138, the toggle lever being pivotably attached to the member 128 by a riveted pin 140. A knob 142 is cemented or otherwise attached to the toggle lever exteriorly of the switch housing and a toggle block 144, preferably of ceramic material, phenolic resin or other strong, electrically insulating material is attached to the toggle lever within the switch housing at 145. A flexible rubber gasket or the like 146 is preferably fitted within the bushing 122 for weather-sealing to protect the bellows 126. The toggle block 144 has two recesses 148 retaining helical coil compression springs 150, each recess also retaining a slide 152 having a bore 153 and having a roller 154 rotatably attached to the slide by a pin 156 so that the spring biases the slide to move out of the toggle block recess 148. In the arrangement, as illustrated, the rollers 154 are positioned to resiliently engage the respective contact arm means 70 in the separate poles of the switch 10 and are adapted to be moved longitudinally along the contact arm means by movement of the toggle lever 138.

In a preferred construction of the switch 10, the housing liner 20 preferably has a depending portion 158 electrically separating the terminals of the separate switch poles and has a wall 160 within the housing also separating the separate compartments 14 and 16 of the switch. If desired. additional walls may be formed on the liner 20 as indicated by the broken line 162 in FIG. 2 for separating the individual switch contacts within each pole of the switch. In a desirable switch construction, the toggle block 144 has a groove 164 slidably fitted over the liner wall 160 for guiding the toggle block during motion of the toggle lever.

The operation of the switch 10 is as follows. When the toggle actuating means 18 is in the switch position illustrated in FIG. 1, the roller 154 in one switch pole resiliently engages the central portions 74 of the contact arm means 70 for holding the contact arm means in firm electrical contact with the U-shaped bracket 26. In this switch position, the contact arm means is disposed in a generally horizontal position resting on the U-shaped bracket and the depending cars 90 of the contact arm means are in their lowest position. The ears 90 therefore hold the J- shaped pin 112 in its lowest position so that the spring 11-6 is fully compressed depressing the auxiliary contact arm 100 with its resilient member 104 for holding the contact 106 carried by the resilient member in firm electrical contact with the contact 50 mounted on the liner base 30. When the spring 116 is omitted, the end 110 of the ]-shaped pin may directly engage the resilient member 104 for holding the contacts 106 and 50 in engagement. However, the spring 116 is preferably used as shown to assure engagement of the contacts 106 and 50 even if the contacts should be substantially worn away. In this way the switch closes only a single circuit in each switch pole, this circuit extending through the terminal stud 40, the U-shaped bracket 26, the pigtail 118, the resilient member 104 on the auxiliary contact arm 100, and the contact 106 to the contact 50 and the terminal stud 58 attached to the contact 50. The toggle slide 152 is held extended from the recess 148 in the toggle block by the spring 150 so that the rollers 154 cannot move on the contact arm means without riding up on the contact arm portions 74 and compressing the spring 150. Thus the contacts 106 and 50 are held firmly together in good electrical contact. A corresponding circuit is closed in the other pole of the toggle switch as will be understood.

The toggle means 18 is movable to an alternate switch position such as that illustrated in FIG. 5 for opening the circuit above-described and for closing an alternate circuit with the contact 54. For example, pivoting of the toggle means 18 forces the roller 154 to ride up on the portions 74 of the contact arm means 70 compressing the spring 150 in the toggle block. As the roller passes over the end 34 of the U-shaped bracket contact 26 and is moved out onto the end 78 of the contact arm means extending over that end of the U-shaped bracket, the contact arm means 70 is rocked sharply into the position shown in FIG. 5. That is, as the roller passes over the bracket end 34, the spring 150 rapidly extends causing the roller 154 to rock the contact arm means sharply while continuing to maintain good electrical contact between the bracket contact 26 and the resilient member 80 of the contact arm means. When this occurs, the contact 86 carried by the contact arm means is engaged with the contact S4 with snap action, flexing of the resilient member 80 providing a wiping action between the contacts 86 and 54 to assure good electrical contact therebetween. The flexibility of the resilient member 80 also serves to damp any tendency for the contact 86 to bounce as it engages the contact 54. The rigid member 72 in the contact arm means bears down on the resilient member 80 to assure that the contacts are retained in good electrical contact even under conditions of severe vibration. As the contact arm means rocks to this new switch position, the ears 90 and the I-shaped pin 112 are elevated for lifting the auxiliary contact arm 100 together with the resilient member 104 and the contact 106 sharply away from the contact 50 opening the circuit formed with the contact 50 with snap action. Although the auxiliary contact arm has only limited angular movement, this arm is rigid and its distal end is located beneath the resilient member 104 to move the contact 106 sharply away from the contact 50 even if there should be some tendency for the contact 106 to stick to the contact 50. In this way, movement of the toggle means 18 opens one circuit and substantially simultaneously closes an alternate circuit, this alternate circuit extending through the terminal stud 40, the U-shaped bracket 26, the resilient member 80 on the contact 54 arm means and the contact 86 to the contact 54 and the terminal stud 58 attached to the contact 54.

As will be understood, movement of the toggle means 18 from the position shown in FIG. 5 to the position shown in FIG. 1 opens the circuit between the contacts 86 and 54 with snap action and recloses the circuit between the contacts 106 and 50. Similarly movement of the toggle means 18 to the right from the position shown in FIG. 1 moves the roller 154 to the left onto the end portion 76 of the rigid member 72 rocking the contact arm means to another position, indicated by the broken lines 166 in FIG. 5, for opening the circuit between the contacts 106 and 50 and for closing another alternate circuit between the contacts 84 and '52. This latter alternate circuit extends through the terminal stud 40, the bracket contact 26, the resilient member of the contact arm means 70 and the contact 84 to the contact 52 and the terminal stud 58 attached to the contact 52.

Thus the three-position switch 10 of this invention is adapted to close alternate circuits between the common bracket contact 26 and each of the additional contacts 50, 52 and 54. The switch holds contacts firmly together in closed circuit position; the switch brings contacts together for closing each circuit with wiping action to assure good electrical connection between the switch contacts; and the switch contacts are brought together or moved apart to close or open switch circuits with snap action to minimize contact wear. In addition, the single spring in each switch pole serves to hold pairs of the switch contacts together with substantially equal pressure in closing each of the three switch circuits. Further, the switch 10 is of compact, simple, and inexpensive construction while being adapted for long use under conditions of severe vibration.

It should be understood that although particular embodiments of the invention have been described by way of illustration, this invention includes all modifications and equivalents of the illustrated embodiments falling within the scope of the appended claims.

What is claimed is:

1. A toggle switch for alternately closing one of three circuits comprising an electrical insulating base, a common electrically conductive U-shaped bracket contact having its central portion secured to said base and its two ends upstanding from said base, three additional electrically conductive contacts mounted on said base in spaced relation to each other and to said common contact, an auxiliary electrically-conductive contact arm means electrically connected to said common contact, and means mounting said contact arm for pivotal movement relative to one of said additional contacts, a main electrically conductive contact arm means mounted for pivotal movement on said common contact, and means connecting to said auxiliary contact arm and main contact arm for holding said auxiliary contact arm in engagement with said one additional contact to close one circuit between said common contact and said one additional contact, toggle means mounted on said base engaging said main contact arm means for holding said one circuit closed, said toggle means being movable for rocking said main contact arm means on said common contact into engagement with respective additional contacts to close alternate circuits between said common contact and said respective additional contacts and for pivoting said auxiliary contact arm out of engagement with said one additional contact to open said one circuit.

2. A toggle switch as set forth in claim 4 wherein said means mounting said auxiliary contact arm comprises a pivot pin secured to said common bracket contact extending laterally thereupon, said auxiliary contact arm means being mounted for pivotal movement on said pin.

3. A toggle switch as set forth in claim 2 wherein said auxiliary contact arm means includes a rigid arm member pivotably mounted at one end in said pin, a resilient strip secured at one end to said rigid arm, and an electrically conductive contact mounted on the distal end of said resilient strip for wiping engagement with said one additional contact.

4. A toggle switch as set forth in claim 1 wherein said main contact arm means includes a rigid arm member, a resilient strip secured at its central portion to the central portion of said rigid arm, and a pair of electrically conductive contacts mounted on respective distal ends of said resilient strip for wiping engagement with respective additional contacts.

5. A toggle switch as set forth in claim 4 wherein said means connecting said auxiliary arm comprises means mounting a I pin beneath said rigid arm extending laterally therefrom, and spring means mounted on said pin engaging said auxiliary contact arm means for connecting said main contact arm means and said auxiliary contact arm means.

6. A toggle switch for alternately closing one of three circuits comprising an electrically insulating base, a common electrically-conductive U-shaped bracket contact having its central portion secured to said base and its ends upstanding from said base, three additional electrically conductive contacts mounted in said base in spaced relation to each other and to said common contact, a pivot pin secured to said common bracket contact extending laterally therefrom, a rigid auxiliary contact arm pivotably mounted on said pin, a first electrically conductive resilient strip secured at one end to said auxiliary contact arm and electrically connected to said bracket contact, a contact mounted on the distal end of said resilient strip, a rigid main contact arm, a second electrically-conductive resilient strip secured at its central portion to the central portion of said main contact arm, a pair of contacts mounted on respective distal ends of said strip, said main contact arm being rested on said upstanding ends of said common bracket with said second resilient strip electrically connected to said bracket, said main contact arm having a central depressed portion extending downward between said bracket ends, means connecting said auxiliary contact arm to the central portion of said main contact arm for movement therewith, and toggle means resiliently engaging said central portion of said main contact arm for holding said auxiliary arm contact in engagement with one of said additional contacts to close one circuit between said bracket contact and said one additional contact, said toggle means being movable to two alternate positions engaging respective opposite ends of said main contact arm for rocking said main contact arm on said bracket contact to engage said main arm contacts with said additional contacts to close respective alternate circuits between said bracket contact and additional contacts and to pivot said auxiliary contact arm to open said one circuit.

7. A toggle switch as set forth in claim 6 wherein said auxiliary contact arm and first resilient strip have aligned apertures therethrough, said means connecting said auxiliary contact arm to said main contact arm comprise ear members depending from said main contact arm, a J- shaped pin supported on said ears and having one end extending through said aligned apertures, and spring means mounted in said one end of said J-shaped pin for resiliently holding said auxiliary contact arm in engagement with said one additional contact.

8. A multi-pole toggle switch for alternately closing one of three circuits in each pole between a common contact and three additional contacts in each pole comprising an electrically insulating base, a common electrically conductive U-shaped bracket contact in each pole having its central portion secured to said base and having its two ends upstanding from said base, three additional electrically conductive contacts in each pole mounted on said base in spaced relation to each other and to said common contact, an electrically conductive contact arm means rested across said two ends of each common contact and engaged with one additional contact for closing a first circuit in each pole, and a single toggle means resiliently engaging all of said contact arm means for holding said contact arm means in position to close said first circuits, said toggle means being movable to rock said contact arm means on said common contacts into engagement with either of two additional contacts in each pole to close respective alternate circuits in each pole and to simultaneously open said first circuits.

9. A multi-pole toggle switch for alternately closing one of three circuits in each pole between a common contact and three additional contacts in each pole comprising an electrically insulating base, a common electrically-conductive U-shaped bracket contact in each pole having its central portion secured to said base and having its two ends upstanding from said base, three additional electrically conductive contacts in each pole mounted on said base in spaced relation to each other and to said common contact, a pivot pin secured to each common bracket contact extending laterally therefrom, an auxiliary contact arm means pivotally mounted on each pin for movement relative to one additional contact, a main electrically conductive contact arm means rested across said two ends of each common contact and connected to one of said auxiliary contact arm means, and a single toggle means resiliently engaging a central portion of each of said main contact arm means to hold each auxiliary contact arm means in engagement with said one additional contact for closing a first circuit in each pole, said toggle means being movable to engage either of two end portions of each of said main contact arm means for rocking said main contact arm means on said common contacts into engagement with respective additional contacts to close either of two alternate circuits in each pole and for pivoting said auxiliary contact arm means out of engagement with said one additional contact to open said first circuits.

References Cited UNITED STATES PATENTS 2,849,549 8/1958 Elliott.

2,857,485 10/ 1958 Brooks.

2,961,519 11/1960 Sandowsky et al 2O0-68 3,022,394 2/1962 Grotz ZOO-68 ROBERT S. MACON, Primary Examiner DAVID SMITH, JR., Assistant Examiner 

